


Wormy and Pals

by Sexy-Rex (Cazuki)



Category: Undertale (Video Game)
Genre: Fontcest, M/M, Mating Cycles/In Heat, Pre-Established Relationship, Some implicit sin, but mostly explicit sin, not-so-innocent Papyrus, some pathetic attempts at humour
Language: English
Status: Completed
Published: 2016-07-12
Updated: 2016-07-12
Packaged: 2018-07-23 14:50:51
Rating: Not Rated
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,511
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/7467522
Author URL: https://archiveofourown.org/users/Cazuki/pseuds/Sexy-Rex
Summary: <blockquote class="userstuff">
              <p>The time has come once again and Sans finds himself having to deal with one of his dreaded heat-cycles. Every other time he has dealt with the maddening pleasure in silence. But this time, he has someone to help him.</p><p>(Repost from dummy account, because who needs shame!)</p>
            </blockquote>





	Wormy and Pals

**Author's Note:**

> Based on the wonderful comic by Sanspar!

Monster heats are many things. At best, they are annoyances that can cause a monster to shut themselves away for a while. At worst, they are periods of tortuous agony where the unlucky victim would spend hours, maybe even days, locked in a cycle of seemingly never-ending unsatiated lust. The scale and effects of a monster’s heat can vary drastically on species, gender, time of year and other conditioning factors. However, despite all of these differences, the first warning signs of a monster heat are well-documented and are typically universal across all monster species.

The first sign is almost always light-headedness.

 

* * *

 

“…shit…” Sans balled one bony fist against his skull, gently massaging the tough bone in a desperate attempt to clear his foggy mind. Normally, Sans wasn’t the type of monster to swear, but predicaments like this one called for extra special treatment… never mind the fact that Sans hated his heats with a burning (ha, ha funny) passion.

Ever since his first heat, Sans had learned to hate the burning sensation that assaulted his frame with his whole being. He hated the way he couldn’t think clearly or sleep for the burning that numbed his bones. He hated that, even when he tried to deal with the burning, it would just re-appear an hour or so after he was done, leaving him mad with desire yet exhausted at the same time. He hated how he’d have to tip-toe around the house, washing sheets and soiled clothing, his soul thumping out of his rib-cage as he prayed to whatever deity existed that his younger brother wouldn’t find him.

Thinking about Papyrus, Sans had another thing to add to the long, long list.

Two months ago, the brothers had finally, _finally_ , broken down the wall that had been keeping them apart for so long. It had been an eternity coming, not that Sans had particularly done anything to help the situation. Since then, life had become a state of pure bliss for Sans. If they weren’t cooking together, making a mess of their small kitchen, they were watching TV, nervous hands fumbling for each other and interlocking like two pieces of a puzzle. If they weren’t out on ‘guard-duty’, openly guffawing and secretly smiling at each other’s crummy jokes, they were napping together, an activity that Sans _always_ loved to share. They did everything together. They talked, they hugged, they kissed. They’d even connected in the most intimate way any two monsters could… once.

While the start of their relationship had been ignited by that single night of devoted passion two months ago, since then, neither brother had brought up the subject of having sex again. It wasn’t that Sans didn’t _want_ to. Lord Asgore did he want to. But old habits die hard… especially when you’re already an undead (heheh). He was just so happy right now and why should he risk all of that for his own selfish desires?

So now Sans had to suffer being locked away inside his room, both his body and his heart writhing in agony, losing both his reason and contact with the monster he loved the most in the whole universe. Of course, he hadn’t told Papyrus what was really happening to him. For all his brother knew, Sans was just dealing with a small bout of the flu. And so here he was, sitting among his dishevelled blankets and pillows, sweat pouring down his skeleton in droves, forming a small wet patch on the sheets. His whole frame was trembling as if cold, but it was distinctly warm to the touch, his barely restrained magic intensifying every light brush of his undershirt against his bones. His soul could barely contain itself in his rib-cage, a royal blue light brightening the space around him. He felt and looked like a mess.

Luckily, Papyrus had gone out with Undyne for training, so at least Sans could take solace in the fact the house was empty. It was a good thing too. Sans had noticed the warning signs early enough to convince Papyrus he was sick, but only now was the heat really beginning to take hold.

“grgh…!” Magic crackled in the surrounding air, making loud snapping sounds as it concentrated and dispersed erratically. Sans’ soul grew heavier, glowing brighter as he felt a familiar discomfort form around his pelvis. “a-argh… fuck!”

Instinctively, Sans bucked into the feeling, rubbing himself against the course material of his shorts. The delicious friction only made the discomfort of the confinement stronger. After a few small, stuttering thrusts, Sans whimpered. Bony hands reached down to push away the hem of his shorts, revealing himself to the cold open air. His wild magic continued to crackle, solidifying into three familiar tendrils. The tendrils coiled and swirled around his body, feeling through air; searching for something. A mate.

Too ashamed to looked down, Sans grabbed himself. He hissed, the chill of his bones contrasting with the heat of the concentrated magic. He started taking deep breaths, mellowing himself out and accepting he would just have to play with his trombone alone (damn him and his puns). He slowly started to flick his wrist-

**_BANG!_ **

Sans’ soul almost leapt right out of his rib-cage as the front door slammed against a wall. His hand flinched away as a booming voice travelled into his room, as loud as if the cause was there himself.

“BROTHER?! I, THE _GREAT_ PAPYRUS, HAVE COME HOME EARLY TO SEE HOW YOU ARE DOING!” Footsteps thundered against the wooden floor, quickly growing louder and closer as they neared Sans’ door.

 _shit!_ Panicking, Sans reached out with the small amount of magic he still controlled, enveloping the door knob in blue magic. Just as he did, Papyrus’ footsteps reached the door and stopped, the knob turning in what should have been an opening motion.

“HMM…? BROTHER?” The knob twisted again and Sans held it tightly, his body burning. “IS THERE SOMETHING WRONG WITH YOUR DOOR? ARE YOU ALRIGHT?” Sans opened his mouth to speak, horrified when his voice came out as a squeak.

“NO-“ he coughed, “urhmm! i mean… yeah bro, i’m totally fine… just, y’know…? sleeping…” Sans coughed again, loud enough for Papyrus to hear. “still pretty ‘under the weather’? hehe… get it? ‘cause i’m short?” Okay, that was bad, even for him. For a moment, Papyrus was silent and a small glimmer of hope told Sans that maybe his brother would buy it. That hope was shattered when Papyrus spoke again.

“Sans.”

 _oh fuckk~_ Sans throbbed, a wave of heat cascading through him. He _loved_ when Papyrus used that voice. His quiet, authoritative voice. Sans felt his grip on his magic weaken, the tentacles snaking around him, telling him to give it up. Sans was listening too, his grip becoming weaker and weaker as Papyrus continued speaking.

“Are you sure, you’re okay? I haven’t heard from you all day, not even by phone. I know you need sleep and all but… I’m worried about your health Sans.”

Sans phalanges traced down to his pelvis again. Grabbing the magic there, he started flicking his wrist in a circular motion. In some distant part of his mind he was screaming; pervert, pervert, pervert. But the rest didn’t care, electric pleasure spurring him on as his hand became slicked in bright blue pre.

“Sans? Can you hear me?” Sans couldn’t help a little mewl.

“yeah pa-ahp! i’m hmm! i’m here.”

“Oh gosh! You sound terrible. Come on and let me- “The door knob twisted again and Sans, too distracted to hold it, seized up as the door swung inwards, revealing Pap’s concerned face. “-in. OH! YOU LET ME IN! NOW LET’S SEE WHAT’S WRO- “Papyrus froze mid-sentence, eye-sockets widening as he took in the scene. Sans' skull bright blue, bony hand caressing his magic appendage, hazy white pupils staring directly at him and thick tendrils coiling around his frame. “…oh.”

Suddenly, Papyrus’ whole skull lit up in florescent orange, gloved hands moving to cover his eye-sockets. “Oh gosh! I am so, so sorry Sans. I didn’t know you were-“

“don’t be.” Sans spit out the words. His lust started speaking for him, driving away his insecurity. Gosh darnit, he wanted this. He _needed_ this. Right now. “just… pap… can you… come over here? _please_?” Sans was begging and he knew it. All he could do was stare at Papyrus, mewling as he continued his desperate attempt to relieve himself. Papyrus uncovered his eyes, skull still glowing. He took another look, hesitating, and then padded forward. Another heat-wave flushed through Sans and his tentacles writhed in delight.

Papyrus perched himself on the edge of the bed next to Sans. His pupils roved around the room, obviously trying not to focus on the show Sans was putting on for him. Sans chuckled. _so cute…_

“H-HEY, WHAT ARE YOU-?!” Sans swung himself around, straddling Papyrus’ pelvis and forcing his younger brother back onto the bed. Sans looked into his brother’s eye-sockets, pupils smouldering. Papyrus was surprised for a second before his skull relaxed into an expression of awe and… arousal?

Papyrus moved and Sans followed, touching their teeth together with a soft clank. Before either of them knew it, their ecto-tongues formed, allowing Sans to deepen the kiss. He gently took hold of Papyrus’ skull, tilting it up and to the side to allow him better access.

“Mnn…” They both moaned into the kiss, revelling in each other’s connection. Papyrus sucked playfully on Sans’ tongue, making Sans shudder and a fresh bout of pre drip down on his shorts. “ahmngh…!” _God_ did he love it when Papyrus did that.

They could have stayed like that literally forever, but a particularly intense wave forced Sans backwards. He groaned, grinding his hips against Papyrus’ armoured pelvis, hazy pupils staring down at his prey. Papyrus’ pupils were almost as big as his sockets, dilated and focusing purely on him. Good.

Suddenly, one of his tendrils slithered into view, redirecting their attention. The tentacle seemed to look at Sans, coiling questioningly. Sans nodded, understanding implicitly. The tentacle wriggled giddily, racing down, bumping its head lightly against the crown of Papyrus’ skull.

“Wha-?” Papyrus twitched, pushing himself up onto his elbows, pupils following the translucent tendril. Sans chuckled.

“hehe. seems wormy likes you, bro.” Wormy the tentacle bumped against Papyrus’ skull again in a sort of kiss, before flopping itself onto his head, snuggling onto the bone. Papyrus’ jaw dropped.

“SANS!?” He whined. “YOU _NAMED_ IT!?” Sans grinned, his joke-master nature reawakening.

“sure i did!” He indicated to the two tentacles behind him. “and these two are squirmy and bob.”

“SANSSS,” Papyrus groaned, mashing the heel of his hand against his skull. “THAT IS THE MOST RIDCULOUS THING I HAVE EVER HEARD! YOU SHOULDN’T NAME-“

“aw c’mon bro.” Wormy, sensing they were being talked about, slide down Papyrus’ cheekbone, bumping its head against Papyrus’ teeth. “he likes youu~”.

Papyrus’ blush deepened, pupils focusing on the affectionate tendril.

“Fine…” he murmured, “but only because they’re yours.” Papyrus clanked his teeth against the tentacle. Flames seized Sans’ bones, his pelvis throbbing in annoyance at his neglect.

“mnna-ah! o-oh… stars!” He only barely bit back a curse. He ground his hips hard onto Papyrus, the friction barely reaching him through his shorts. “hnn~” he whimpered.

“Sans! Are you alright!?” Sans grunted.

“no. i’m not. the heat… its my he-eeat.” Papyrus’ pupils widened, realization dawning. Silence settled between them as Sans continued to fruitlessly push his pelvis against Papyrus’. He was too far gone. The numbing heat was consuming him. “pa-ahp… I need your help… _please_!” Papyrus jolted back into focus, blush covering his whole skull.

“I-I!...” his pupils flickered desperately. It wasn’t like he didn’t want to! It was just… Sans looked like he was in so much pain and Papyrus didn’t want to make it worse. However, when Sans looked at him, neon tears threatening to fall, Papyrus didn’t think. He reached down past the tentacle and grabbed the solid, dripping ectoplasm.

The effect was immediate. “a-ah!” Sans mewled, pupils rolling into the back of his skull, tongue lolling from his mandible, dripping onto Papyrus’s armour. Sans jolted upright, thrusting his pelvis into Papyrus’ strokes, covering his red glove in blue pre. The tendrils, sensing the change in atmosphere, surged towards Papyrus, wrapping around his rib-cage. With one wrapped around his back, the other two started exploring the rest of his frame, sliding down his armour before finding the empty space below. They slipped inside, sliding along his sensitive ribs, teasing each one and covering them in blue fluid.

Papyrus gripped Sans tighter. “W-wowie! That f-feels-!” Papyrus keened loudly as the tendrils found a particularly sensitive set of ribs. Papyrus’ threw his skull back, leaning into Wormy for support. “AAH!”

Sans panted above him, sockets shut, single-mindedly thrusting. Oh god, it felt _so_ much better. Even through the glove, Sans could feel the rough contours of Papyrus’ phalanges and the lack of control increased his pleasure ten-fold. He bent forward, licking Papyrus’ cheek, moaning into his ear-hole. Papyrus’ breath shuddered, his jaw opening on impulse. Sans dove in, licking and sucking everywhere his impossibly long tongue could reach. He pushed Papyrus onto the bed, trapping him between his arms, his thrusts becoming rougher, pressure building in his chest.

“mmm!” Sans drew back, biting down on the lip of his undershirt, muffling his cries. He was so close! Come on! Justa…couple-! “Mnnnn~…ooohh.” Sweet release spurted thick and fast, coating their clothes in blue. Sans gasped, riding the cool waves of relief flushing through his bones. He hung suspended, mind dead to everything but his own satisfaction.

It wasn’t until he heard a loud polite cough that he was brought back to reality. He focused on Papyrus below him, tentacles momentarily still as they too were rocked by pleasure.

“b-bro?” he stammered, realization dawning. Oh, Lord Asgore what had he done!? “oh my g-osh, pap! i am so sorry! i didn’t mean to i-“

“Ssssh.” Papyrus placed a gloved finger, covered in blue come, against Sans’ teeth. “It’s okay Sans, you didn’t hurt me… in fact…uhmm…” Papyrus paused, orange blue deepening as he looked down. Sans followed his eyes. His pupils widened when he saw a distinct orange glow shining through Papyrus’ armour. Oh… Sans felt the magic around his pelvis flutter back into life. This was far from over.

Heat again numbed his brief spell of lucidity and he looked back up at his brother. He smiled.

“of course! can’t leave you out of the fun after all.” Papyrus’ expression softened, happy he hadn’t had to say something embarrassingly lewd. Sans felt a flush of his own at that innocent smile. “uhmm! well! could you give me a hand?” Papyrus grinned.

“Only if you let me!”

Despite himself, a smile pulled up the corners of Sans’ mandible. Yep, he loved Papyrus alright… and he would be sure to express that love again and again, for as long as his heat controlled him… and maybe a bit after that too.


End file.
